Inferior ulnar collateral artery

At a glance

English

Inferior ulnar collateral artery

Latin (TA2)

Arteria collateralis ulnaris inferior

System

Artery

Region

Upper limb

Side

Paired, left and right

About the inferior ulnar collateral artery

The inferior ulnar collateral artery, sometimes called the supratrochlear artery or by its old name arteria anastomotica magna, is one of the lowest branches of the brachial artery. It leaves the medial side of the parent vessel roughly five centimetres above the elbow crease, in the lower part of the arm, well below the superior ulnar collateral artery.

From its origin it heads medially across the front of brachialis. It then pierces the medial intermuscular septum and winds behind the humerus, between the bone and triceps brachii, just above the olecranon fossa. Here it meets branches of the deep artery of the arm (the middle collateral artery), and together they make an arterial loop over the fossa on the back of the elbow.

Its branches feed the network around the medial side of the joint. While the artery lies on brachialis, some twigs run upwards and link with the superior ulnar collateral artery, and others pass down anterior to the medial epicondyle to meet the anterior ulnar recurrent artery from the forearm. Behind the medial epicondyle another branch joins the superior ulnar collateral artery and the posterior ulnar recurrent artery. It also supplies small muscular branches to brachialis, pronator teres and triceps near the elbow.

Through these connections the inferior ulnar collateral artery is part of the cubital anastomosis, the ring of collateral channels that links the brachial artery above the elbow with the radial and ulnar arteries below. If the brachial artery is tied or blocked below the origin of its collateral branches, this network can carry enough blood around the elbow to keep the forearm and hand alive. The artery lies near the median nerve as it starts and near the ulnar nerve behind the epicondyle, which is relevant in surgery on the distal humerus.

Course and supply

Arises from

The medial side of the brachial artery, about five centimetres above the elbow.

Ends in

Ends in the anastomoses around the elbow, forming a loop just over the olecranon fossa with the deep artery of the arm and joining the superior ulnar collateral and the anterior and posterior ulnar recurrent arteries.

Supplies

Supplies brachialis, the lower part of triceps and nearby muscles, and contributes to the collateral network around the medial side of the elbow joint.